1. Field of the Invention
The present invention relates to power cylinder and more particularly, to a rodless power cylinder.
2. Description of the Related Art
A rodless power cylinder is known comprising a cylinder body, a piston assembly mounted inside the cylinder body, a movable member mounted around the cylinder body to carry a machine and coupled with a magnetic coupling thereof to a magnetic coupling of the piston assembly by a magnetic force for synchronous reciprocation with the piston assembly. This design of rodless power cylinder has neither means to effectively control the reciprocating motion and positioning of the piston assembly subject to the operation of the machine that is carried by the movable member, nor means to accurately control feeding and discharge of a compressed flow of air or fluid into or out of the cylinder body in causing the piston assembly to reciprocate, nor sensor means to sense the position of the magnet at each of two opposite ends of the piston assembly for accurately buffering or correcting the reciprocating motion of the piston assembly.
Further, attached means, for example, touch control switch means or laser link optical switch means may be provided at each of the two opposite ends of the cylinder body for controlling a respective valve to supply a compressed flow of air or fluid into the inside of the cylinder body or to discharge the compressed flow of air or fluid out of the cylinder body, thereby controlling the reciprocating motion of the piston assembly accurately subject to the operation of the machine that is carried on the movable member around the cylinder body. However, this measure cannot eliminate human errors to ensure accurate control of the reciprocating motion of the piston assembly, resulting in low performance. Therefore, there is still room for improvement.
In view of the aforesaid problems, it is desirable to provide ideal and effective means for controlling relative actions between valves and movable member of a rodless power cylinder.